Life Cycle of Convective Systems over Western Colombia Meiry Sakamoto Uiversidade de São Paulo, São Paulo, Brazil
Colombia Life Cycle of Convective Systems over Western Colombia
Convective System (CS) identification Infrared satellite images from CPC/NCEP/NWS for 2003 (4 km horizontal resolution at sub satellite point, 30 min. intervals) t t+ t t t+ t ForTraCC (Forecast and Tracking of active Convective Cells) Vila et al, 2008 Temperature threshold of 235K Minimum cluster of 150 pixels (2,400 km²) Life cycle 6 hours t t t+ t Moisture Source Identification Lagrangean Model (Flexpart) applied to ECMWF operational analysis (1 x1 resolution, 6 hours intervals, 60 vertical levels) Stohl and James (2004,2005)
Mesoscale Convective Systems Observed During 2003 hour (UTC)
Life Cycle (hours) Relative Frequency (%) Life Cycle of Convective Systems over Western Colombia 14 12 Oceanic MCS 10 Relative Frequency (%) 8 6 4 2 0 18 16 14 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Months of 2003 Oceanic MCS Life Cycle (hours) 12 10 8 6 4 2 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Relative Frequency (%) Relative Frequency (%) Life Cycle of Convective Systems over Western Colombia 100 90 80 West East Displacement (July 2003) 70 60 50 40 30 20 10 0 100 90 80 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual West East Oceanic MCS 70 60 50 40 30 20 10 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual
Relative Frequency (%) Relative Frequency (%) Life Cycle of Convective Systems over Western Colombia 30 25 20 Initial Phase Mature Phase Dissipation Phase Diurnal Cycle 15 10 5 Diurnal Cycle Oceanic MCS 0 30 25 20 15 10 00_<03 03_<06 06_<09 09_<12 12_<15 15_<18 18_<21 21_<00 Initial Phase Mature Phase Dissipation Phase Oceanic MCS Period (UTC) 5 0 00_<03 03_<06 06_<09 09_<12 12_<15 15_<18 18_<21 21_<00 Period (UTC)
31Jan, 11.0h, SE 26Feb, 8.5h, NW Moisture Source to Oceanic MCS 18Mar, 11h, SW 23Apr, 14.5h, NW
10May, 7.5h, NE 10Jun, 19.5h, NW Moisture Source to Oceanic MCS 20Jul, 16h, SE 23Aug, 14h, SW
21Sep, 10h, NW 30Oct, 26h, SW Moisture Source to Oceanic MCS 7Nov, 22h, SW 14Dec, 18h, SW
12Jan, 20h, SW 11Feb, 11h, SW Moisture Source to 29mar, 11.5h, NW 29Apr, 16h, NW
10May, 28h, NW 26Jun, 9h, SW Moisture Source to 18Jul, 27.5h, SW 31Aug, 12h, SW
24Sep, 18.5h, SW 21Oct, 10.5h, NW Moisture Source to 16Nov, 10h, SW 26Dec, 21h, SW
Summary Continental and oceanic MCS s are more numerous during boreal summer and autumn. Oceanic systems have shorter life cycles than continental ones. In continent, systems generated in May, June and July present longer life cycle. Westward displacement is a trend in continental and oceanic systems, except in January, February and March. Continental systems are mainly generated in the afternoon or early night, their mature phase can happen at night or early morning. Dissipation happens during all day long. Oceanic systems have their genesis and mature phases more frequently during evening and early morning, and dissipation is observed all day with a peak at afternoon. The moisture source to systems initiated in Pacific ocean: December-May: tropical North Atlantic and Caribbean Sea, and in some events the Chilean Pacific May-September: Amazonia and Chilean Pacific October-November: Chilean-Peruvian Pacific and the Caribbean Sea To continental systems moisture comes from: Life Cycle of Convective Systems over Western Colombia December-March: tropical North Atlantic and Caribbean Sea April-May: Amazonia, the tropical North Atlantic, and the Chilean-Peruvian Pacific May-July: from the tropical North Atlantic and the Amazon basin July-October: from Amazonia, the Chilean-Peruvian Pacific, and even from high latitude South America November: tropical Atlantic, Amazonia and the Peruvian Pacific
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